Spark-plug.



C. F. ARNOLD.

SPARK PLUG.

APPLICATION FILED m1. z. 1916 PatentedNov. 21, 1916.

Lil /W25 Inventor Attorneys CARL F. ARNOLD, OF WATSON VILLE, CALIFORNIA.-

SPARK-PLUG.

Specification of Letters Patent.

Application filed February 7,1916. Serial No. 76,663.

To all whom it may concern Be it known that I, CARL F. ARNOLD, a citizen of the United States, residing at Watsonville, in the county of Santa Cruz and State of California, have invented a new and useful Spark-Plug, of which the following is a specification.

he present invention appertains to igniters or spark plugs for internal combustion engines, andaims to provide a novel and improved device of that Character.

It is the object of the invention to provide a spark plug provided with means whereby two or more sparks will be provided, for quickly and effectively igniting the charge, and whereby there is little or no liability of a short circuit occurring between the electrodes.

Another object of the invention is the provision of an attachment which may be applied to spark plugs now in use, without entailing prohibitive trouble or expense, and cooperable with the shell and central electrode of a spark plug to provide a plurality of spark gaps.

It is also within the scope of the invention to provide a spark plug having the improved features above noted, and which at the same time is comparatively simple, compact and inexpensive in construction, as well as being thoroughly practical, reliable and eflicient in use.

With the foregoing and other objects in view which will appear as the description proceeds, the invention resides in the combination and arrangement of parts and in the details of construction hereinafter described and claimed, it being understood that changes in the precise embodiment of the invention herein disclosed, can be made within the scope of what is claimed, without departing from the spirit of the invention.

The invention is illustrated in the accompanying drawing, wherein Figure 1 is a median longitudinal section of the plug, portions being shown in elevation. Fig. 2 is a cross section taken on the line 22 of Fig. 1.

The improvements are illustrated as being applied to a spark plug of ordinary construction, although it is to be understood that the improvements can be employed in various ordinary plugs or in a plug of special construction.

The plug illustrated mcludes'a shell 1 constructed of metal, and having secured theren 1n the ordinary manner an insulator or insulating bushing 2, which carries at its inner end the central electrode 3. The electrode which is usually carried by the shell 1 is removed or omitted, and the inner end of the shell 1 is reduced and exteriorly threaded, as at 4.

The present attachment includes asleeve or ring 5 of metal, which is threaded onto the reduced terminal 4 of the shell 1, so as to be electrically connected with and in reality constitutes a part of the shell. The free end of the sleeve 5 has an inturned annular flange or lip 6, and an arcuate or semi-circular electrode 7 has its ends engaged to diametrically opposite points ofthe free end of the sleeve 5, so that the electrode 7 bridges or spans the sleeve.

Fitted within the sleeve 5 is an annular insulator 8, constructed of porcelain or other insulating material, and having the opposite ends of its aperture countersunk as at 9'and 10, thereby providing an inner annular ridge or rib 11.

A. metallicring 12 is fitted within the aperture of the insulator 8, and is provided with an annular series of flexible or bendable fingers '13 projecting therefrom and extending' across the ridge 11, the free ends of the fingers 13 being bent to overlap'the counter-- sunk portion 9 which faces the interior of the shell 1, whereby the ring 12 is fastened to the ridge of the insulator 8. The ring'12 is provided with a pair of diametrically opposite outstanding electrodes 14 projecting out of the insulator 8 and preferably diverging slightly from one another. The ends of the electrodes 14 are arranged adjacent the electrode 7 to provide a'pair of spark gaps, and the electrode 3 projects within the ring 12 to provide an annular spark gap therebetween. The ring 12 provides a neutral or intermediate electrode member between the insulated electrode 3, and the grounded electrode 7 connected to-the shell 1. The ring 12 can be turned slightly within the insulator 8, if desired, thereby to change the sizes of the spark gaps between the neutral electrodes 14 and the grounded electrode 7, and it is evident that when the sleeve 5 is threaded upon the reduced terminal 4 of the shell 1, the ring 12 will be brought to a position to surround the terminal of the electrode 3.

Patented Nov. 21, 1916.

In employing the present attachment in connection with an ordinary spark plug, it is only necessary to turn down and thread the terminal of the shell 1, as at 4 for the attachment of the sleeve 5. The insulator 8 is .held within the sleeve 5 by the rib 6, and when the sleeve 5 is threaded into place, the insulator 8 will be clamped between the rib or flange 6 and the terminal 4 of the shell 1.

lVhen the spark plug is used, an electric current in traversing the plug, must jump across two spark gaps at least, one between the electrode 3 and ring 12, and one between one of the electrodes 14 and the grounded electrode 7, thus producing at least two sparks. project within the combustion chamber of the engine, whereby the charge is properly ignited by the sparks, and there may be a plurality of sparks between the electrode 3 and ring 12, and a plurality of sparks between the electrodes 14 and 7. By the provision ofthe plurality of separate and distinct sparkgaps, a plurality of sparks are provided, and furthermore, the liability of a short circuit occurring is reduced to a minimum.

Having thus described the invention, what is claimed as new is '1. A spark plug attachment including a sleeve attachable to the shell of a spark plug, an arcuate electrode terminally secured to one end of the sleeve to bridge the same, an annular insulator fitted within the sleeve, and a ring fitted within the in- Sula-tor to surround the electrode of the spark plug, and having an electrode 00- operating with the arcuate electrode.

2. A spark plug including a shell having a reduced terminal, an insulator within the shell, an electrode carried by the insulator and projecting from the reduced terminal of the shell, a sleeve fitted upon said terminal, an annular insulator fitted within the sleeve and held thereby against said terminal, an electrode carried by the free end of the sleeve, and a ring fitted within an annular insulator surrounding the first, mentioned electrode and having an electrode copies of this patent may be obtained for The present device is adapted to for cooperating with the second mentioned electrode.

3. A spark plug having a shell, an insulator therein, an electrode carried by said insulator an electrode grounded to the shell, an annular insulator assembled with the shell between the first mentioned insulator and the second v mentioned electrode, and a ring fitted within the annular insulator surrounding the first mentioned electrode and having an electrode projecting therefrom and cooperating with the second mentioned "electrode, there being an annular spark gap between the first mentioned electrode and the ring, and the spark gap between the first and second mentioned electrodes being adjustable when either the annular insulator or ring are rotated relative to the second mentioned electrode.

4. A spark plug attachment including a sleeve attachable to the shell of a spark plug, an electrode carried by the sleeve to be grounded to the shell, an annular insulator fitted within the sleeve, and a ring fitted within the insulator and having an electrode cooperating with the aforesaid electrode, said ring being adapted to surround the insulated electrode of the spark plug.

5. A spark plug attachment including a sleeve having an inturned flange at one end, an arcuate electrode terminally attached to said end of the sleeve to bridge the same, an annular insulator fitted within the sleeve to bear against said flange and having an inner annular ridge, a ring fitted within the insulator and havin fingers extending across said ridge and ent to hold the ring in place, said ring having opposite electrodes cooperating with the aforesaid electrode, and said ring being adapted to surround the insulated electrode of a spark plug.

In testimony that I claim the foregoing as my own, I have hereto aflixed my signature in the presence of two witnesses.

CARL F. ARNOLD. Witnesses:

Gnonon W. Jonas, 0; R. TAYLOR.

five cents each, .by addressing the "Commissioner or lamb. Washington, D. G. 

